1. Field of the Invention
This invention relates to a gate driver, and in particular, to a gate driver with an input buffer.
2. Background of the Invention
A liquid crystal display device includes a substrate and other related driving device. Further, there are a plurality of data lines and scan lines on the substrate, and a plurality of pixels that are defined by the intersection of the plurality of data lines and the plurality of scan lines. In order to display a frame, a source driver and a gate driver respectively provide a data signal and a scan signal to the corresponding data lines and the scan lines, as a result, each pixel will display a predetermined brightness and color. Besides, the gate driver can be coupled to the display device on the substrate.
FIG. 1A is a simplified diagram showing a plurality of gate drivers arranged on a substrate of a display device. In the FIG. 1A, the gate drivers 113, 115, and 117 are arranged on the substrate 110, and all are connected to reference voltages VSH and VSL via the wiring on the substrate 110. However, due to the resistance variation between the wiring, there must be a different voltage drop while a current flows through the wiring. The phenomenon is meant to be an “IR drop” on the wiring, resulting in different voltage values on different positions of the wiring. Consequently, the gate driver 113 receives input voltages VSH1 and VSL1, the gate driver 115 receives input voltages VSH2 and VSL2, and the gate driver 117 receives input voltages VSH3 and VSL3, where the values of each input voltage VSH1, VSH2 and VSH3 are different from each other. Additionally, the values of each input voltage VSL1, VSL2 and VSL3 are also different from each other as well. As described above, due to voltage drop variations caused by the current flowing through the wiring, the input voltages of the gate drivers 113, 115 and 117 are not the same, thus, the voltage output from the gate drivers 113, 115 and 117 differs from their predetermined voltage values. Therefore, it may be advantageous to adopt other configurations for arranging the plurality of gate drivers on the substrate.
Referring to FIG. 1B, showing a simplified diagram of a plurality of gate drivers on a display device, gate drivers 123, 125 and 127 are configured on the substrate 120 and connected by the wiring on substrate 120. The gate driver 123 is coupled to the reference voltage VSH and VSL and receives input voltages VSH4 and VSL4. The gate driver 125 is connected to gate driver 123 and receives input voltages VSH5 and VSL5. The gate driver 127 is also connected to the gate driver 125 and receives input voltages VSH6 and VSL6.
Similarly, due to the voltage drop caused by the current flowing through the wiring, the input voltages of the gate driver 123, 125 and 127 are not the same, thus, voltage output from the gate drivers 123, 125 and 127 differs from their predetermined voltage values.